Slumlord

I felt like a slumlord.

As he hasn't kept up the building at all, there is no other term for him but "slumlord."

Coordinate term: slumlady

The slumlord was collecting over $100 a month for this horrible place.

The first rule in the slumlord business is: “The poorer the tenant, the bigger the profit!” The explanation is simplicity itself. For example, a poor family needs a two-room apartment, but can't afford the $40.00 a month rent. So you divide the two rooms into four smaller apartments, and rent each one for $20.00 a month. The poor families are happy with the low rent, and the slumlord is happy with the increased profit.

The guy's a real bastard, a real slumlord. He never did anything to maintain the place. He wouldn't give us a written lease—we only had a verbal agreement.